From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751010AbVJXGBL (ORCPT ); Mon, 24 Oct 2005 02:01:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751011AbVJXGBL (ORCPT ); Mon, 24 Oct 2005 02:01:11 -0400 Received: from sv1.valinux.co.jp ([210.128.90.2]:11679 "EHLO sv1.valinux.co.jp") by vger.kernel.org with ESMTP id S1751002AbVJXGBK (ORCPT ); Mon, 24 Oct 2005 02:01:10 -0400 Date: Mon, 24 Oct 2005 14:52:58 +0900 (JST) Message-Id: <20051024.145258.98349934.taka@valinux.co.jp> To: pj@sgi.com Cc: akpm@osdl.org, Simon.Derr@bull.net, linux-kernel@vger.kernel.org, clameter@sgi.com, torvalds@osdl.org, linux-mm@kvack.org Subject: Re: [PATCH] cpuset confine pdflush to its cpuset From: Hirokazu Takahashi In-Reply-To: <20051024001913.7030.71597.sendpatchset@jackhammer.engr.sgi.com> References: <20051024001913.7030.71597.sendpatchset@jackhammer.engr.sgi.com> X-Mailer: Mew version 2.2 on Emacs 20.7 / Mule 4.0 (HANANOEN) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi Paul, I realized CPUSETS has another problem around pdflush. Some cpuset may make most of pages in it dirty, while the others don't. In this case, pdflush may not start since the ratio of the dirty pages in the box may be less than the watermark, which is defined globally. This may probably make it hard to allocate pages from the cpuset or the nodes it depends on. This wouldn't be good for NUMA machine without cpusets either. Do you have any plans about it? > This patch keeps pdflush daemons on the same cpuset as their > parent, the kthread daemon. > > Some large NUMA configurations put as much as they can of > kernel threads and other classic Unix load in what's called a > bootcpuset, keeping the rest of the system free for dedicated > jobs. > > This effort is thwarted by pdflush, which dynamically destroys > and recreates pdflush daemons depending on load. Thanks, Hirokazu Takahashi.